/*
 * Copyright (C) 2005 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#define LOG_TAG "Vector"

#include <stdio.h>
#include <stdlib.h>

#include <utils/Errors.h>
#include <utils/VectorImpl.h>

#include <utils/Log.h>

#include "SharedBuffer.h"

/*****************************************************************************/


namespace android {

// ----------------------------------------------------------------------------

    const size_t kMinVectorCapacity = 4;

    static inline size_t max(size_t a, size_t b) {
        return a > b ? a : b;
    }

// ----------------------------------------------------------------------------

    VectorImpl::VectorImpl(size_t itemSize, uint32_t flags)
            : mStorage(0), mCount(0), mFlags(flags), mItemSize(itemSize) {
    }

    VectorImpl::VectorImpl(const VectorImpl &rhs)
            : mStorage(rhs.mStorage), mCount(rhs.mCount),
              mFlags(rhs.mFlags), mItemSize(rhs.mItemSize) {
        if (mStorage) {
            SharedBuffer::bufferFromData(mStorage)->acquire();
        }
    }

    VectorImpl::~VectorImpl() {
        LOGW_IF(mCount,
                "[%p] subclasses of VectorImpl must call finish_vector()"
                        " in their destructor. Leaking %d bytes.",
                this, (int) (mCount * mItemSize));
        // We can't call _do_destroy() here because the vtable is already gone.
    }

    VectorImpl &VectorImpl::operator=(const VectorImpl &rhs) {
//        LOG_ALWAYS_FATAL_IF(mItemSize != rhs.mItemSize,
//        "Vector<> have different types (this=%p, rhs=%p)", this, &rhs);
        if (this != &rhs) {
            release_storage();
            if (rhs.mCount) {
                mStorage = rhs.mStorage;
                mCount = rhs.mCount;
                SharedBuffer::bufferFromData(mStorage)->acquire();
            } else {
                mStorage = 0;
                mCount = 0;
            }
        }
        return *this;
    }

    void *VectorImpl::editArrayImpl() {
        if (mStorage) {
            const SharedBuffer *sb = SharedBuffer::bufferFromData(mStorage);
            SharedBuffer *editable = sb->attemptEdit();
            if (editable == 0) {
                // If we're here, we're not the only owner of the buffer.
                // We must make a copy of it.
                editable = SharedBuffer::alloc(sb->size());
                // Fail instead of returning a pointer to storage that's not
                // editable. Otherwise we'd be editing the contents of a buffer
                // for which we're not the only owner, which is undefined behaviour.
//                LOG_ALWAYS_FATAL_IF(editable == NULL);
                _do_copy(editable->data(), mStorage, mCount);
                release_storage();
                mStorage = editable->data();
            }
        }
        return mStorage;
    }

    size_t VectorImpl::capacity() const {
        if (mStorage) {
            return SharedBuffer::bufferFromData(mStorage)->size() / mItemSize;
        }
        return 0;
    }

    ssize_t VectorImpl::insertVectorAt(const VectorImpl &vector, size_t index) {
        return insertArrayAt(vector.arrayImpl(), index, vector.size());
    }

    ssize_t VectorImpl::appendVector(const VectorImpl &vector) {
        return insertVectorAt(vector, size());
    }

    ssize_t VectorImpl::insertArrayAt(const void *array, size_t index, size_t length) {
        if (index > size())
            return BAD_INDEX;
        void *where = _grow(index, length);
        if (where) {
            _do_copy(where, array, length);
        }
        return where ? index : (ssize_t) NO_MEMORY;
    }

    ssize_t VectorImpl::appendArray(const void *array, size_t length) {
        return insertArrayAt(array, size(), length);
    }

    ssize_t VectorImpl::insertAt(size_t index, size_t numItems) {
        return insertAt(0, index, numItems);
    }

    ssize_t VectorImpl::insertAt(const void *item, size_t index, size_t numItems) {
        if (index > size())
            return BAD_INDEX;
        void *where = _grow(index, numItems);
        if (where) {
            if (item) {
                _do_splat(where, item, numItems);
            } else {
                _do_construct(where, numItems);
            }
        }
        return where ? index : (ssize_t) NO_MEMORY;
    }

    static int sortProxy(const void *lhs, const void *rhs, void *func) {
        return (*(VectorImpl::compar_t) func)(lhs, rhs);
    }

    status_t VectorImpl::sort(VectorImpl::compar_t cmp) {
        return sort(sortProxy, (void *) cmp);
    }

    status_t VectorImpl::sort(VectorImpl::compar_r_t cmp, void *state) {
        // the sort must be stable. we're using insertion sort which
        // is well suited for small and already sorted arrays
        // for big arrays, it could be better to use mergesort
        const ssize_t count = size();
        if (count > 1) {
            void *array = const_cast<void *>(arrayImpl());
            void *temp = 0;
            ssize_t i = 1;
            while (i < count) {
                void *item = reinterpret_cast<char *>(array) + mItemSize * (i);
                void *curr = reinterpret_cast<char *>(array) + mItemSize * (i - 1);
                if (cmp(curr, item, state) > 0) {

                    if (!temp) {
                        // we're going to have to modify the array...
                        array = editArrayImpl();
                        if (!array) return NO_MEMORY;
                        temp = malloc(mItemSize);
                        if (!temp) return NO_MEMORY;
                        item = reinterpret_cast<char *>(array) + mItemSize * (i);
                        curr = reinterpret_cast<char *>(array) + mItemSize * (i - 1);
                    } else {
                        _do_destroy(temp, 1);
                    }

                    _do_copy(temp, item, 1);

                    ssize_t j = i - 1;
                    void *next = reinterpret_cast<char *>(array) + mItemSize * (i);
                    do {
                        _do_destroy(next, 1);
                        _do_copy(next, curr, 1);
                        next = curr;
                        --j;
                        curr = NULL;
                        if (j >= 0) {
                            curr = reinterpret_cast<char *>(array) + mItemSize * (j);
                        }
                    } while (j >= 0 && (cmp(curr, temp, state) > 0));

                    _do_destroy(next, 1);
                    _do_copy(next, temp, 1);
                }
                i++;
            }

            if (temp) {
                _do_destroy(temp, 1);
                free(temp);
            }
        }
        return NO_ERROR;
    }

    void VectorImpl::pop() {
        if (size())
            removeItemsAt(size() - 1, 1);
    }

    void VectorImpl::push() {
        push(0);
    }

    void VectorImpl::push(const void *item) {
        insertAt(item, size());
    }

    ssize_t VectorImpl::add() {
        return add(0);
    }

    ssize_t VectorImpl::add(const void *item) {
        return insertAt(item, size());
    }

    ssize_t VectorImpl::replaceAt(size_t index) {
        return replaceAt(0, index);
    }

    ssize_t VectorImpl::replaceAt(const void *prototype, size_t index) {
        ALOG_ASSERT(index < size(),
                    "[%p] replace: index=%d, size=%d", this, (int) index, (int) size());

        if (index >= size()) {
            return BAD_INDEX;
        }

        void *item = editItemLocation(index);
        if (item != prototype) {
            if (item == 0)
                return NO_MEMORY;
            _do_destroy(item, 1);
            if (prototype == 0) {
                _do_construct(item, 1);
            } else {
                _do_copy(item, prototype, 1);
            }
        }
        return ssize_t(index);
    }

    ssize_t VectorImpl::removeItemsAt(size_t index, size_t count) {
        ALOG_ASSERT((index + count) <= size(),
                    "[%p] remove: index=%d, count=%d, size=%d",
                    this, (int) index, (int) count, (int) size());

        if ((index + count) > size())
            return BAD_VALUE;
        _shrink(index, count);
        return index;
    }

    void VectorImpl::finish_vector() {
        release_storage();
        mStorage = 0;
        mCount = 0;
    }

    void VectorImpl::clear() {
        _shrink(0, mCount);
    }

    void *VectorImpl::editItemLocation(size_t index) {
        ALOG_ASSERT(index < capacity(),
                    "[%p] editItemLocation: index=%d, capacity=%d, count=%d",
                    this, (int) index, (int) capacity(), (int) mCount);

        if (index < capacity()) {
            void *buffer = editArrayImpl();
            if (buffer) {
                return reinterpret_cast<char *>(buffer) + index * mItemSize;
            }
        }
        return 0;
    }

    const void *VectorImpl::itemLocation(size_t index) const {
        ALOG_ASSERT(index < capacity(),
                    "[%p] itemLocation: index=%d, capacity=%d, count=%d",
                    this, (int) index, (int) capacity(), (int) mCount);

        if (index < capacity()) {
            const void *buffer = arrayImpl();
            if (buffer) {
                return reinterpret_cast<const char *>(buffer) + index * mItemSize;
            }
        }
        return 0;
    }

    ssize_t VectorImpl::setCapacity(size_t new_capacity) {
        // The capacity must always be greater than or equal to the size
        // of this vector.
        if (new_capacity <= size()) {
            return capacity();
        }

        size_t new_allocation_size = 0;
//        LOG_ALWAYS_FATAL_IF(!safe_mul(&new_allocation_size, new_capacity, mItemSize));
        SharedBuffer *sb = SharedBuffer::alloc(new_allocation_size);
        if (sb) {
            void *array = sb->data();
            _do_copy(array, mStorage, size());
            release_storage();
            mStorage = const_cast<void *>(array);
        } else {
            return NO_MEMORY;
        }
        return new_capacity;
    }

    ssize_t VectorImpl::resize(size_t size) {
        ssize_t result = NO_ERROR;
        if (size > mCount) {
            result = insertAt(mCount, size - mCount);
        } else if (size < mCount) {
            result = removeItemsAt(size, mCount - size);
        }
        return result < 0 ? result : size;
    }

    void VectorImpl::release_storage() {
        if (mStorage) {
            const SharedBuffer *sb = SharedBuffer::bufferFromData(mStorage);
            if (sb->release(SharedBuffer::eKeepStorage) == 1) {
                _do_destroy(mStorage, mCount);
                SharedBuffer::dealloc(sb);
            }
        }
    }

    void *VectorImpl::_grow(size_t where, size_t amount) {
        ALOGV("_grow(this=%p, where=%d, amount=%d) count=%d, capacity=%d",
              this, (int) where, (int) amount, (int) mCount, (int) capacity());

        ALOG_ASSERT(where <= mCount,
                    "[%p] _grow: where=%d, amount=%d, count=%d",
                    this, (int) where, (int) amount, (int) mCount); // caller already checked

        size_t new_size;
//        LOG_ALWAYS_FATAL_IF(!safe_add(&new_size, mCount, amount), "new_size overflow");

        if (capacity() < new_size) {
            // NOTE: This implementation used to resize vectors as per ((3*x + 1) / 2)
            // (sigh..). Also note, the " + 1" was necessary to handle the special case
            // where x == 1, where the resized_capacity will be equal to the old
            // capacity without the +1. The old calculation wouldn't work properly
            // if x was zero.
            //
            // This approximates the old calculation, using (x + (x/2) + 1) instead.
            size_t new_capacity = 0;
//            LOG_ALWAYS_FATAL_IF(!safe_add(&new_capacity, new_size, (new_size / 2)),
//                                "new_capacity overflow");
//            LOG_ALWAYS_FATAL_IF(!safe_add(&new_capacity, new_capacity, static_cast<size_t>(1u)),
//                                "new_capacity overflow");
            new_capacity = max(kMinVectorCapacity, new_capacity);

            size_t new_alloc_size = 0;
//            LOG_ALWAYS_FATAL_IF(!safe_mul(&new_alloc_size, new_capacity, mItemSize),
//                                "new_alloc_size overflow");

//        ALOGV("grow vector %p, new_capacity=%d", this, (int)new_capacity);
            if ((mStorage) &&
                (mCount == where) &&
                (mFlags & HAS_TRIVIAL_COPY) &&
                (mFlags & HAS_TRIVIAL_DTOR)) {
                const SharedBuffer *cur_sb = SharedBuffer::bufferFromData(mStorage);
                SharedBuffer *sb = cur_sb->editResize(new_alloc_size);
                if (sb) {
                    mStorage = sb->data();
                } else {
                    return NULL;
                }
            } else {
                SharedBuffer *sb = SharedBuffer::alloc(new_alloc_size);
                if (sb) {
                    void *array = sb->data();
                    if (where != 0) {
                        _do_copy(array, mStorage, where);
                    }
                    if (where != mCount) {
                        const void *from =
                                reinterpret_cast<const uint8_t *>(mStorage) + where * mItemSize;
                        void *dest =
                                reinterpret_cast<uint8_t *>(array) + (where + amount) * mItemSize;
                        _do_copy(dest, from, mCount - where);
                    }
                    release_storage();
                    mStorage = const_cast<void *>(array);
                } else {
                    return NULL;
                }
            }
        } else {
            void *array = editArrayImpl();
            if (where != mCount) {
                const void *from = reinterpret_cast<const uint8_t *>(array) + where * mItemSize;
                void *to = reinterpret_cast<uint8_t *>(array) + (where + amount) * mItemSize;
                _do_move_forward(to, from, mCount - where);
            }
        }
        mCount = new_size;
        void *free_space = const_cast<void *>(itemLocation(where));
        return free_space;
    }

    void VectorImpl::_shrink(size_t where, size_t amount) {
        if (!mStorage)
            return;

//    ALOGV("_shrink(this=%p, where=%d, amount=%d) count=%d, capacity=%d",
//        this, (int)where, (int)amount, (int)mCount, (int)capacity());

        ALOG_ASSERT(where + amount <= mCount,
                    "[%p] _shrink: where=%d, amount=%d, count=%d",
                    this, (int) where, (int) amount, (int) mCount); // caller already checked

        size_t new_size;
//        LOG_ALWAYS_FATAL_IF(!safe_sub(&new_size, mCount, amount));

        if (new_size < (capacity() / 2)) {
            // NOTE: (new_size * 2) is safe because capacity didn't overflow and
            // new_size < (capacity / 2)).
            const size_t new_capacity = max(kMinVectorCapacity, new_size * 2);

            // NOTE: (new_capacity * mItemSize), (where * mItemSize) and
            // ((where + amount) * mItemSize) beyond this point are safe because
            // we are always reducing the capacity of the underlying SharedBuffer.
            // In other words, (old_capacity * mItemSize) did not overflow, and
            // where < (where + amount) < new_capacity < old_capacity.
            if ((where == new_size) &&
                (mFlags & HAS_TRIVIAL_COPY) &&
                (mFlags & HAS_TRIVIAL_DTOR)) {
                const SharedBuffer *cur_sb = SharedBuffer::bufferFromData(mStorage);
                SharedBuffer *sb = cur_sb->editResize(new_capacity * mItemSize);
                if (sb) {
                    mStorage = sb->data();
                } else {
                    return;
                }
            } else {
                SharedBuffer *sb = SharedBuffer::alloc(new_capacity * mItemSize);
                if (sb) {
                    void *array = sb->data();
                    if (where != 0) {
                        _do_copy(array, mStorage, where);
                    }
                    if (where != new_size) {
                        const void *from = reinterpret_cast<const uint8_t *>(mStorage) +
                                           (where + amount) * mItemSize;
                        void *dest = reinterpret_cast<uint8_t *>(array) + where * mItemSize;
                        _do_copy(dest, from, new_size - where);
                    }
                    release_storage();
                    mStorage = const_cast<void *>(array);
                } else {
                    return;
                }
            }
        } else {
            void *array = editArrayImpl();
            void *to = reinterpret_cast<uint8_t *>(array) + where * mItemSize;
            _do_destroy(to, amount);
            if (where != new_size) {
                const void *from =
                        reinterpret_cast<uint8_t *>(array) + (where + amount) * mItemSize;
                _do_move_backward(to, from, new_size - where);
            }
        }
        mCount = new_size;
    }

    size_t VectorImpl::itemSize() const {
        return mItemSize;
    }

    void VectorImpl::_do_construct(void *storage, size_t num) const {
        if (!(mFlags & HAS_TRIVIAL_CTOR)) {
            do_construct(storage, num);
        }
    }

    void VectorImpl::_do_destroy(void *storage, size_t num) const {
        if (!(mFlags & HAS_TRIVIAL_DTOR)) {
            do_destroy(storage, num);
        }
    }

    void VectorImpl::_do_copy(void *dest, const void *from, size_t num) const {
        if (!(mFlags & HAS_TRIVIAL_COPY)) {
            do_copy(dest, from, num);
        } else {
            memcpy(dest, from, num * itemSize());
        }
    }

    void VectorImpl::_do_splat(void *dest, const void *item, size_t num) const {
        do_splat(dest, item, num);
    }

    void VectorImpl::_do_move_forward(void *dest, const void *from, size_t num) const {
        do_move_forward(dest, from, num);
    }

    void VectorImpl::_do_move_backward(void *dest, const void *from, size_t num) const {
        do_move_backward(dest, from, num);
    }

/*****************************************************************************/

    SortedVectorImpl::SortedVectorImpl(size_t itemSize, uint32_t flags)
            : VectorImpl(itemSize, flags) {
    }

    SortedVectorImpl::SortedVectorImpl(const VectorImpl &rhs)
            : VectorImpl(rhs) {
    }

    SortedVectorImpl::~SortedVectorImpl() {
    }

    SortedVectorImpl &SortedVectorImpl::operator=(const SortedVectorImpl &rhs) {
        return static_cast<SortedVectorImpl &>( VectorImpl::operator=(
                static_cast<const VectorImpl &>(rhs)));
    }

    ssize_t SortedVectorImpl::indexOf(const void *item) const {
        return _indexOrderOf(item);
    }

    size_t SortedVectorImpl::orderOf(const void *item) const {
        size_t o;
        _indexOrderOf(item, &o);
        return o;
    }

    ssize_t SortedVectorImpl::_indexOrderOf(const void *item, size_t *order) const {
        if (order) *order = 0;
        if (isEmpty()) {
            return NAME_NOT_FOUND;
        }
        // binary search
        ssize_t err = NAME_NOT_FOUND;
        ssize_t l = 0;
        ssize_t h = size() - 1;
        ssize_t mid;
        const void *a = arrayImpl();
        const size_t s = itemSize();
        while (l <= h) {
            mid = l + (h - l) / 2;
            const void *const curr = reinterpret_cast<const char *>(a) + (mid * s);
            const int c = do_compare(curr, item);
            if (c == 0) {
                err = l = mid;
                break;
            } else if (c < 0) {
                l = mid + 1;
            } else {
                h = mid - 1;
            }
        }
        if (order) *order = l;
        return err;
    }

    ssize_t SortedVectorImpl::add(const void *item) {
        size_t order;
        ssize_t index = _indexOrderOf(item, &order);
        if (index < 0) {
            index = VectorImpl::insertAt(item, order, 1);
        } else {
            index = VectorImpl::replaceAt(item, index);
        }
        return index;
    }

    ssize_t SortedVectorImpl::merge(const VectorImpl &vector) {
        // naive merge...
        if (!vector.isEmpty()) {
            const void *buffer = vector.arrayImpl();
            const size_t is = itemSize();
            size_t s = vector.size();
            for (size_t i = 0; i < s; i++) {
                ssize_t err = add(reinterpret_cast<const char *>(buffer) + i * is);
                if (err < 0) {
                    return err;
                }
            }
        }
        return NO_ERROR;
    }

    ssize_t SortedVectorImpl::merge(const SortedVectorImpl &vector) {
        // we've merging a sorted vector... nice!
        ssize_t err = NO_ERROR;
        if (!vector.isEmpty()) {
            // first take care of the case where the vectors are sorted together
            if (do_compare(vector.itemLocation(vector.size() - 1), arrayImpl()) <= 0) {
                err = VectorImpl::insertVectorAt(static_cast<const VectorImpl &>(vector), 0);
            } else if (do_compare(vector.arrayImpl(), itemLocation(size() - 1)) >= 0) {
                err = VectorImpl::appendVector(static_cast<const VectorImpl &>(vector));
            } else {
                // this could be made a little better
                err = merge(static_cast<const VectorImpl &>(vector));
            }
        }
        return err;
    }

    ssize_t SortedVectorImpl::remove(const void *item) {
        ssize_t i = indexOf(item);
        if (i >= 0) {
            VectorImpl::removeItemsAt(i, 1);
        }
        return i;
    }

/*****************************************************************************/

}; // namespace android

